Some readers may recall from our last newsletter (Fall, 2009) that Craig Roesier, A DNR biologist, discovered that rusty crayfish populations are declining in several lakes in northern Wisconsin. A fluke names //Microphallus// was found in them in most of those lakes. He recently completed report shows that in lakes where populations are still high, no //Microphallus// were found. One of these lakes was Plum Lake, where the vegetation seemed to be recovering--which is in turn, an indication that crayfish population is declining. Indeed, Plum Lake rusty crayfish had the highest concentration of fluke larvae of any lake studied. Does this mean the rusties will decline significantly in Plum Lake. We hope so. What about Star Lake? Will the vegetation come back in our lakes?
It is way to early to tell. These findings are promising, but very preliminary. These flukes have several alternate hosts. We don't know if those big mystery snails that have recently shown up are involved or not. What birds or mammals are involved? We don't know yet!
We also don't know what new studies the DNR will sanction for this year. However, the lakes Committee plans to start some rusty crayfish population studies in Star and Plum. We plan to inspect the livers of captured crayfish to see how many larvae they have in them. This of course, means that we are going to need volunteers to help trap, measure, sex, possibly dissect the crayfish and record data. Are you interested in helping us? Call 542-3108 for more information.